1. Field of the Invention
The invention relates to a spatial light modulator (SLM) and a method for color management thereof, and more particularly, to a SLM and a method for color management thereof through adjusting shapes and arrangements of pixels and subpixels.
2. Description of the Prior Art
SLM is an application of the photoelectric system, which has the advantages of adjusting wavelengths, phases, and polarization of lights, and can be applied to optical signal treatments, amplifying images, and transferring incoherent lights into coherent lights. Accordingly, with the arrival of the digital age, the use of SLMs has become more and more popular in every field. A liquid crystal on silicon (LCOS) display is one kind of SLM that combines the technologies of semiconductors and LCDs. The LCOS display can provide images with high resolution and high lightness. In addition, the LCOS display has a structure simpler than other kinds of SLMs, so that the LCOS display has a potential of low cost and has become popular in the digital projection field.
The main structure of an LCOS display includes a light source module, a LCOS panel, and a color separation and combination optical system. Generally speaking, the LCOS display can be divided into three-panel LCOS displays and single-panel LCOS displays according to the type of optical engine. The three-panel type optical engine separates lights generated from light source into red, blue, and green lights through plurality of prisms, projects those lights into three separated LCOS panels respectively, and combines those three lights from LCOS panels to form colored images. The single-panel type optical engine utilizes a color wheel to form red, blue, and green lights sequentially from white lights, and synchronizes the three kinds of lights with single-colored images, the red, blue, and green images, of the LCOS panel formed by driving programs so as to produce color-separated images sequentially. Since human eyes have the persistence of vision, people can see colored images from the projected images.
Please refer to FIG. 1, which is a schematic diagram of a portion of an LCOS panel 10 according to the prior art. The LCOS panel 10 comprises pluralities of rectangular pixels 12 arranged in a pixel array. When the pixel transistors (not shown) positioned on the substrate of the LCOS panel 10 are opened, the corresponding liquid crystal molecules twist according to driving signals so that light can pass through the liquid crystal materials to create images. Accordingly, a conventional LCOS panel only reflects lights with a single color depending on the driving signals of pixels but cannot provide the functionality of managing colors.
On the other hand, in a conventional SLM, the pixels of the pixel array are all rectangular. Please refer to FIG. 2, which is an enlarged view of the pixel shown in FIG. 1. The conventional pixel 40 has a rectangular shape. Therefore, when the red, blue, and green subpixels are positioned in the conventional pixel 40, the conventional subpixels have to be designed as rectangular shapes and all have the same size, as the subpixels 42, 44, 46 show in FIG. 2. Taking the subpixel 42 as an example, a dotted line connecting the four vertexes of the rectangular subpixel 42 approximately forms an ellipse. Consequently, the areas of the rectangular subpixels 42, 44, 46 are not circular, and therefore the conventional subpixels 42, 44, 46 cannot provide either preferable images or the functionality of color management according to the color and image requirements of manufacturers.